* Sound data and database management fundamentals, concepts, principles and methods for the thinking professional and user.
* Dispelling myths and misconceptions about the relational model and its practical implications.
* Making theoretical foundations accessible to the practitioner.

MENU

Tuesday, May 27, 2014

Weekly Update

1. Quote of the Week

Codd's relational model is based on set theory, and set theory simply doesn't work for database systems. It can't, for example, model a gum ball machine. Gum balls, you see, have only one attribute, which is color (gum balls don't have names, serial numbers, bar codes, or URLs). If you put 200 gum balls in a gum ball machine, the gum ball machines contains 200 gum balls. If you try to put 200 gum balls in a gum ball relation, you get a relation of 5 gum balls (the number of colors) and 195 duplicate errors. If you then take 5 gum balls out of the gum ball machine, it still contains 195 gum balls. If you take 5 gum balls out of the gum ball relation, it goes empty. --Jim Starkey, LinkedIn.com

2 comments:

That nonsense makes me wonder how many other dbms developers there are who have no clue as to the fundamental use of a dbms, let alone an rdbms. It is pretty sad for the industry when anybody dreams that the example of an undefined application can show the unsuitability of a particular technique - there is no suitable data technique for any undefined app, not rdbms, not SQL, not NOSQL. Not the first time I've noticed LinkedIn has no editors.

Here, relations about gumballs are equated with gumballs themselves. JS should try to think what McCarthy meant when he said that submarines can't swim. One can't talk about a dbms application or application data model unless one is capable of stating the kinds of sentences one wants to manipulate. Dbms developers who aren't capable of that are very liable to produce what's not needed. Could this be a reason why we have so many dbms products that are off the mark, for example confusing concurrency theory with relational theory, etc., etc.?

It also appears that JS can't distinguish between an application about gumballs and an application about gumball machines. Besides, of course gumballs often have UPC codes, I've seen them. Some of them even have names stamped on them. Not to mention flavours, sugar content, etc., etc. Before JS dumps any more code on the world, he should practice defining a few applications, it appears he doesn't know the problem he thinks he's solving.